Typically, communication satellites are used as element or part of a communication link and entirely or partially replace a terrestrial communication network. In the present case, a communication link is understood as comprising those components that are arranged between two communicating devices and serve the purpose of transmitting data between these devices. Also, communication satellites may serve to connect user devices with access points (may also be referred to as transition point) to a terrestrial communication network, so that the user devices are connected to the communication network.
Advantageously, communication satellites may be used to connect user devices located in infrastructurally less developed regions of the earth or regions not developed at all to a communication network. This may be the case if terrestrial access points to the communication network completely lack or cannot be provided at all, e.g., in sparsely populated areas of the earth or on wide water areas.
Communication satellites comprise at least two interfaces. Signals from a user device are received via an interface on the user side or are sent to the user device via this interface, and signals are sent to the communication network or are received therefrom via an interface on the network side. In general, satellites have the advantage that they circle the earth and, hence, may connect almost any point of the surface of the earth to a communication network. However, also such a satellite requires a remote station that is connected to the terrestrial communication network.